No way to automatically do it, but you can "quickly" do it. Just change the round durations on the Rounds tab.
To do this quickly, switch the view to "Spreadsheet" (press the View button). Set the cursor in the Duration column of the first round (the first round you need to change the duration of) and change it to "10". Now select "10" and copy it (Ctrl+C). Now just press the down cursor, then Ctrl+V, over and over until you've updated all of the remaining rounds.